The vast majority of users aren't - and can't - stay with just one platform, but have to combine Windows, Mac, iOS, Android and Linux devices.
Evernote works on all platforms.
Onenote works on all except Linux.
Outline needs to keep up, yet I don't see the Windows or Android versions in the roadmap.
Linux Mint and some other distros are now fully usable by a layperson straight out of the box, and with W10 being still a problematic software I expect Linux to become more mainstream. Creating a Windows program that could be ran under Wine in Linux would cover both environments.